This invention relates to the production of ductile sheet articles, such as metal siding panels, formed to simulate the appearance of building materials or the like having plural adjacent surfaces lying in diverging planes. In a specific sense, the invention is directed to horizontally elongated metal siding panels formed to resemble a row of wooden shake-type shingles, and to procedures for producing such panels.
For purposes of illustration, the invention will be described herein with particular reference to aluminum siding panels, it being understood that the term "aluminum" embraces aluminum metal and alloys thereof, and that the term "siding panels" includes panels suitable for installation on roofs as well as on walls.
Roll-formed aluminum siding panels are widely employed for cladding exterior walls of buildings. Typically, such panels are mounted one above another in parallel, overlapping, interlocked relation, each panel having a longitudinal bead or lip formed along its upper margin and a longitudinal inwardly bent channel flange formed along its lower margin. The panels are nailed or otherwise attached to a wall at their upper margins, which are substantially flush with the wall, and the channel flange of each panel interlocks with the lip of the panel immediately below it to secure the panel lower edge against dislodgment while holding the panel lower edge away from the wall, in a manner simulating the appearance of wooden clapboards. An advantage of panels of this type is that they can be of relatively great length (e.g. twelve feet or more in horizontal extent, with an exposed vertical dimension of, say, eight or ten inches), as is desired for convenience and facility of handling and installation.
While the described clapboard appearance of these panels is satisfactory for many installations, it is frequently desirable to provide other aesthetic or design effects in an exterior wall cladding having the functional advantages of aluminum or other sheet material siding. In particular, it is often desired to provide in such a cladding an appearance simulating wooden shingles of the type commonly known as shakes. Heretofore, however, proposed designs for shingle-simulating metal siding panels have involved difficult forming problems and have in general failed to achieve close resemblance to the true surface appearance of a row of wooden shakes. Moreover, owing in particular to the forming problems involved, the lengths of such shake-simulating panels have been restricted; i.e., it has not been possible to achieve a satisfactory metal panel product which acceptably simulates a row of wooden shakes in surface configuration and is comparable in length to the conventional metal panels described above. Thus, although long horizontal metal siding panels are greatly preferred by siding installers, for results including those mentioned above, no long (e.g. eight feet or more in horizontal dimension) shake-simulating metal panel has heretofore been available.
In explanation of the difficulties involved in attempting to achieve a long shake-simulating metal panel, it may be noted that the exposed surfaces of a row of wooden shakes typically lie in downwardly diverging planes. This feature can be simulated in an aluminum sliding panel by forming therein alternating first and second shingle-simulating portions each extending across the width of the panel with their surfaces respectively lying in downwardly diverging planes. However, because the divergence of these shingle-simulating portions from a common plane is significantly greater at the bottom of the panel than in the upper portion thereof, the bottom margin of the panel is gathered, i.e. effectively shortened in length relative to the upper panel portion. This difference in length may be tolerable if the panel is sufficiently short in horizontal extent, but in the case of the greatly elongated panels (comparable in length to conventional clapboard-like aluminum siding panels), such as are preferred by siding installers, the disparity in length between the lower margin and the upper portion of the panel is so great that is causes unacceptable cambering, bowing, and/or other distortion of the panel.